When the ball screw is running, the temperature rise will affect the accuracy of the mechanical transmission system, especially the high-speed and high-precision machinery. The following factors affect the temperature rise of ball screw:

溫升的因素基本是這三種：(1) 預壓力 (2) 潤滑 (3) 預拉。

There are three basic factors of temperature rise: (1) pre pressure (2) lubrication (3) pre tension.

導軌在安裝時注意的事項

Matters needing attention during installation of guide rail

(1) 預壓力的影響

(1) The influence of preload

為避免造成機械傳動系統的任何失步，提高螺帽剛性是很重要的，然而要提高螺帽剛性，必須使螺帽預壓力達 到一定水準。施加預壓力于螺帽會增加螺牙的摩擦扭矩，并使工作時的溫升提高。

However, it is very important to improve the rigidity of the nut system in order to avoid any loss of mechanical step. Applying pre pressure on the nut will increase the friction torque of the screw teeth and increase the temperature rise during operation.

導軌安裝不好滾珠絲桿的影響

Influence of improper installation of guide rail on ball screw

(2) 潤滑的影響

(2) Effect of lubrication

潤滑油的選擇直接影響滾珠絲桿的溫升。HIWIN滾珠絲桿須採以油或油脂其中一項的潤滑，一般建議以軸承 潤滑油為滾珠絲桿油潤滑，油脂則建議以鋰皂基的油脂。油品黏度選用是依操作速度、工作溫度及負荷情形來做 選擇。說明油品黏度、工作溫度與溫升的關係和IKO自潤滑滾珠花鍵原理是一樣的。

The selection of lubricating oil directly affects the temperature rise of ball screw. HIWIN ball screw must be lubricated with one of oil or grease. Generally, bearing grease is recommended as ball screw oil, and lithium soap based grease is recommended as grease. The selection of oil viscosity depends on the operating speed, operating temperature and load. It shows that the relationship between oil viscosity, working temperature and temperature rise is the same as IKO self-lubricating ball spline.

當工作情況為高速低負載時選用低黏度油品；低速高負載時則建議使用黏度高油品。 一般來講，高速時建議使用潤滑油為40℃時黏度指數范圍為32～68 cSt (ISO VG 32～68)(DIN  51519)；而低速時，建議使用的潤滑油為40℃時黏度指數范圍為90 cSt (ISO VG 90)以上。應用于高速且重負載，必須以強製冷卻來降低溫度，且可藉由中空螺桿通入冷卻油來達到冷卻效果。

When the working condition is high speed and low load, low viscosity oil is selected; when the working condition is low speed and high load, high viscosity oil is recommended. Generally speaking, it is recommended to use lubricating oil at high speed with viscosity index range of 32-68 CST (ISO VG 32-68) (DIN 51519) at 40 ℃; at low speed, it is recommended to use lubricating oil with viscosity index range of above 90 CST (ISO VG 90) at 40 ℃. For high speed and heavy load applications, the temperature must be reduced by forced cooling, and the cooling effect can be achieved by injecting cooling oil into the hollow screw.

(3) 預拉的影響

(3) The influence of pretension

滾珠螺桿溫升時，熱應力效應會使螺桿伸長，使螺桿的長度變得不穩定。其伸長量可藉由M40公式求出，此伸 長量可藉由預拉來做補償；而預拉補償的目標值就是圖面所標示的負T值。過大的預拉會燒壞支撐軸承，因此HIWIN 建議採用小于5℃的預拉值，但若螺桿直徑超過50mm時也不適合做預拉；螺桿直徑大就需要大的預拉力，因此導致 支撐軸承過熱而燒壞。

When the ball screw temperature rises, the thermal stress effect will make the screw elongate and make the screw length unstable. The elongation can be calculated by M40 formula, and the elongation can be compensated by pre stretching. The target value of pre stretching compensation is the negative T value marked on the drawing. Too large pre tension will burn the support bearing, so HIWIN suggests that the pre tension value less than 5 ℃, but it is not suitable for pre tension if the screw diameter exceeds 50 mm; large pre tension is required for large screw diameter, which leads to overheating and burning of the support bearing.